With no time limit on immigration detention, hundreds of people who can't be deported are spending years locked up, with no idea when they will be released or sent home. Human rights lawyers say this breaches detainees' human rights.

The Home Office says some people who spend long periods in detention refuse to cooperate with their own deportation. But as Harriet Grant discovered, the truth is less clear cut.

We hear from Ahmed, who was desperate to go back to Iran, but when the Home Office couldn't get travel documents for him he ended up spending two years in immigration detention. He is now fighting for compensation for the time he spent locked up.

Among those who are resisting removal are many people who have lived most of their lives in the UK, often legally. Rabah discusses his fight to stay in the UK with his family.

Some have won unlawful detention cases, with the help of pressure groups such as Bail for Immigration Detainees. Its head lawyer, Pierre Makhlouf, outlines some of the reasons people get stuck in the system.

Lawyer Stephanie Harrison of Garden Court Chambers wants a time limit on detention, so that if someone cannot be removed they have to be released.

The plights of these prisoners is not a popular political cause. Lib Dem deputy leader Simon Hughes argues against Harrison's proposal - despite the Liberal Democrats' commitment to fight against indefinite detention. The head of the Home Affairs Commons select committee, Labour MP Keith Vaz, blames administrative delay for the continued detention of foreign criminals, and not political posturing.

As the supreme court considers the case of one man who spent five years in immigration detention, a case that will define the powers the Home Office have to detain foreign prisoners while trying to deport them, we look at the story behind the headlines.